ベルマンフォード法 (lib/graph/bellman_ford.hpp)

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• Last update: 2025-06-16 11:48:07+09:00
• Include: #include "lib/graph/bellman_ford.hpp"

Depends on

• 重み付きグラフ (lib/graph/graph.hpp)

Verified with

• test/aoj/grl/bellman_ford.test.cpp

Code

#pragma once
#include <limits>
#include <vector>
#include "graph/graph.hpp"

/// @brief ベルマンフォード法
template <class T>
std::vector<T> bellman_ford(const Graph<T> &graph, int s = 0, T inf = std::numeric_limits<T>::max(),
                            T ninf = std::numeric_limits<T>::lowest()) {
    int n = graph.size();
    std::vector<T> dists(n, inf);
    dists[s] = T();
    bool updated = true;
    for (int count = 0; updated && count <= n << 1; ++count) {
        updated = false;
        for (int i = 0; i < n; ++i) {
            if (dists[i] == inf) continue;
            for (auto &e : graph[i]) {
                if (dists[i] == ninf || dists[i] + e.weight() < dists[e.to()]) {
                    if (dists[e.to()] == ninf) continue;
                    updated = true;
                    if (count >= n) dists[e.to()] = ninf;
                    else dists[e.to()] = dists[i] + e.weight();
                }
            }
        }
    }
    return dists;
}

Traceback (most recent call last):
  File "/home/runner/.local/lib/python3.12/site-packages/competitive_verifier/oj/resolver.py", line 291, in resolve
    bundled_code = language.bundle(path, basedir=basedir)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/.local/lib/python3.12/site-packages/competitive_verifier/oj/verify/languages/cplusplus.py", line 242, in bundle
    bundler.update(path)
  File "/home/runner/.local/lib/python3.12/site-packages/competitive_verifier/oj/verify/languages/cplusplus_bundle.py", line 479, in update
    self._resolve(pathlib.Path(included), included_from=path)
  File "/home/runner/.local/lib/python3.12/site-packages/competitive_verifier/oj/verify/languages/cplusplus_bundle.py", line 286, in _resolve
    raise BundleErrorAt(path, -1, "no such header")
competitive_verifier.oj.verify.languages.cplusplus_bundle.BundleErrorAt: graph/graph.hpp: line -1: no such header

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